John the Ripper is a Quick password cracker, currently available for many flavors of Unix, Windows, DOS, and OpenVMS.

Its main objective is to detect weak Unix passwords. In addition to several crypts (3) most commonly encountered password hash types on several Unix systems supported outside the box are Windows LM hashes, plus many other hashes and figures in the community-enhanced version.

John the Ripper is free and open source software distributed mainly in source code form. If you prefer to use a commercial product tailored to your specific operating system, please consider John the Ripper Pro, which is distributed primarily in the form of "native" packages for the target operating systems and is generally intended to be easier to Install and use and optimum performance.